Yes humans can live with out heads if they are an zombie.
yes. no.
# # #
grass we can always live without grass
Yes, it would be impossible to live without one.
Yes.
No, humans cannot live without establishing a harmonious connection with the ecosystems in the oceans.
yes they can. they actually used to live without humans in herds, until they were domesticated by humans and used for traveling purposes. there are still about 25,000 wild herds of horses.
Nope.
no our brain will dry out
Yes.
no.
Every organism has a head, except for maybe germs etc. but those are single celled organisms. if some organisms had no heads the would not be alive like if humans had no head they would not live because we need our brains to live and our mouths to eat . if we had no heads we would SURELY die!